The NAEP, nicknamed the "nation's report card," is designed to give a snapshot of U.S. educational results by testing samples of students. About 122,000 eighth-graders were tested in 2011.
Average scores increased from 150 to 152, officials said. The percentage of students performing at basic and intermediate levels went up, while the percentage at the advanced level was unchanged.
The gap between black and Hispanic children on the one hand and whites on the other narrowed. Black scores rose an average of 3 percent and Hispanics an average of 5 percent, while white scores only improved by an average of 1 percent.
The gender gap did not narrow. While boys and girls both improved their scores, boys scored, on average, 5 points higher than girls.